Title

Authors

Document Type

Article

Publication Date

3-1989

Abstract

A technique for automated measurement of whole-wafer etch pit density (EPD) for GaAs wafers is presented. The technique relies on an infrared transmission experiment similar to that used to measure EL2 concentration. A theoretical relationship between transmission and EPD is established, including effects due to pit size. The new automated and old visual-count methods are compared on a 3“, low-pressure, liquid-encapsulated Czochralski wafer; it is established that the automated method has much better repeatability. An [EL2] map of this same wafer is also presented.